Considerations for multi-link aggregation

The present Application for Patent is a Continuation of U.S. patent application Ser. No. 16/809,456 by PATIL et al., entitled “DESIGN CONSIDERATIONS FOR MULTI-LINK AGGREGATION” filed Mar. 4, 2020, which claims the benefit of U.S. Provisional Patent Application No. 62/816,028 by PATIL et al., entitled “DESIGN CONSIDERATIONS FOR MULTI-LINK AGGREGATION WHEN THE CHANNELS ARE IN CLOSE PROXIMITY,” filed Mar. 8, 2019, and the benefit of U.S. Provisional Patent Application No. 62/834,316 by PATIL et al., entitled “DESIGN CONSIDERATIONS FOR MULTI-LINK AGGREGATION,” filed Apr. 15, 2019, each of which are assigned to the assignee hereof, and each of which are expressly incorporated herein.

The following relates generally to wireless communications, and more specifically to design considerations for multi-link aggregation.

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). A wireless network, for example a WLAN, such as a Wi-Fi (i.e., Institute of Electrical and Electronics Engineers (IEEE) 802.11) network may include an AP that may communicate with one or more stations (STAs) or mobile devices. The AP may be coupled to a network, such as the Internet, and may enable a mobile device to communicate via the network (or communicate with other devices coupled to the access point). A wireless device may communicate with a network device bi-directionally. For example, in a WLAN, an STA may communicate with an associated AP via downlink (DL) and uplink (UL). The DL (or forward link) may refer to the communication link from the AP to the station, and the UL (or reverse link) may refer to the communication link from the station to the AP.

Some wireless communications systems may support multi-link aggregation, where transmissions may be transmitted and/or received over two or more links between two wireless devices (e.g., two STAs, an AP and STA, etc.). In some cases, a transmission on one link in the multi-link session may interfere with a transmission on one or more other links of the multi-link session. For example, adjacent channel interference (ACI) may result from leakage of signal power from an adjacent channel (due to inadequate filtering, improper tuning, etc.). ACI may negatively impact a communications system, for example by decreasing throughput on adjacent links, increasing signal processing at communicating devices, or incorrectly causing adjacent links to appear busy or occupied, leading to lost transmission opportunities. Improved techniques for ACI management in multi-link aggregation may be desired.

The described techniques relate to improved methods, systems, devices, or apparatuses that support design considerations for multi-link aggregation when channels are in close proximity. In a multi-link aggregation scheme, a first wireless device and a second wireless device may establish multiple wireless links for communicating, such that transmissions or portions of transmission may occur over both links concurrently. Such parallel communications, while benefiting the system in terms of throughput, may increase the complexity of the system. If the links are adjacent, or nearby in frequency, communications over a first channel of a first wireless link may interfere with communications over a second channel of a second wireless link. This type of interference may be referred to as adjacent channel interference (ACI) and may cause a wireless device to falsely detect that the second link is busy. The wireless device may then refrain transmitting on the second link although the link is actually available, which may lead to lost transmission opportunities, increased latency and reduced throughput.

A wireless device described herein, such as a station (STA) or an access point (AP), may implement techniques to ameliorate ACI-related issues. For example, the wireless device may implement techniques based on the induced ACI. In some cases, the wireless device may reduce the transmit power on the initiating link to lessen the impact of ACI on the adjacent link. In some cases, the wireless device may transmit with short interframe spacing (SIFS) bursting on the initiating link and regularly sample on the adjacent link. In some cases, the wireless device may adjust a clear channel assessment (CCA) threshold on the adjacent link such that the CCA threshold is adjusted to below an energy detection threshold. The wireless device may implement techniques to silence other STAs in the basic service set (BSS) so that another STA does not gain control of a second link once the wireless device begins transmission on an initiating link. Further techniques are described herein for generating a Physical Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU) at the wireless device. Techniques described herein may be applied to synchronous or asynchronous systems.

A method of wireless communication at a first wireless device is described. The method may include identifying a message for parallel transmission on at least a first wireless link and a second wireless link of a set of wireless links between the first wireless device and a second wireless device, the set of wireless links supporting parallel transmissions during a multi-link session, performing, during a first time period, a CCA procedure on the first wireless link and the second wireless link, determining, based on the performed CCA procedure, to transmit on the first wireless link and refrain from transmitting on the second wireless link, modifying, for a second time period based on the determining, a transmission parameter for the first wireless link, or a CCA parameter for the second wireless link, or a combination thereof, and performing, during the second time period based on the modifying, the CCA procedure on the second wireless link and transmission of at least a first portion of the message on the first wireless link.

An apparatus for wireless communication at a first wireless device is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to identify a message for parallel transmission on at least a first wireless link and a second wireless link of a set of wireless links between the first wireless device and a second wireless device, the set of wireless links supporting parallel transmissions during a multi-link session, perform, during a first time period, a CCA procedure on the first wireless link and the second wireless link, determine, based on the performed CCA procedure, to transmit on the first wireless link and refrain from transmitting on the second wireless link, modify, for a second time period based on the determining, a transmission parameter for the first wireless link, or a CCA parameter for the second wireless link, or a combination thereof, and perform, during the second time period based on the modifying, the CCA procedure on the second wireless link and transmission of at least a first portion of the message on the first wireless link.

Another apparatus for wireless communication at a first wireless device is described. The apparatus may include means for identifying a message for parallel transmission on at least a first wireless link and a second wireless link of a set of wireless links between the first wireless device and a second wireless device, the set of wireless links supporting parallel transmissions during a multi-link session, performing, during a first time period, a CCA procedure on the first wireless link and the second wireless link, determining, based on the performed CCA procedure, to transmit on the first wireless link and refrain from transmitting on the second wireless link, modifying, for a second time period based on the determining, a transmission parameter for the first wireless link, or a CCA parameter for the second wireless link, or a combination thereof, and performing, during the second time period based on the modifying, the CCA procedure on the second wireless link and transmission of at least a first portion of the message on the first wireless link.

A non-transitory computer-readable medium storing code for wireless communication at a first wireless device is described. The code may include instructions executable by a processor to identify a message for parallel transmission on at least a first wireless link and a second wireless link of a set of wireless links between the first wireless device and a second wireless device, the set of wireless links supporting parallel transmissions during a multi-link session, perform, during a first time period, a CCA procedure on the first wireless link and the second wireless link, determine, based on the performed CCA procedure, to transmit on the first wireless link and refrain from transmitting on the second wireless link, modify, for a second time period based on the determining, a transmission parameter for the first wireless link, or a CCA parameter for the second wireless link, or a combination thereof, and perform, during the second time period based on the modifying, the CCA procedure on the second wireless link and transmission of at least a first portion of the message on the first wireless link.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, performing the transmission on the first wireless link may include operations, features, means, or instructions for transmitting the at least the first portion of the message on the first wireless link according to the modified transmission parameter.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, modifying the transmission parameter may include operations, features, means, or instructions for reducing a first transmission power for the first wireless link to a reduced transmission power during the second time period, the modified transmission power including the reduced transmission power.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, modifying the transmission parameter may include operations, features, means, or instructions for selecting, for the at least the first portion of the message during the second time period, a resource unit that may be narrower than a bandwidth of the first wireless link, the modified transmission parameter including the selected resource unit.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, performing the transmission on the first wireless link may include operations, features, means, or instructions for transmitting the at least the first portion of the message on the first wireless link according to a short interframe spacing (SIFS) burst pattern.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, performing the CCA procedure on the second wireless link may include operations, features, means, or instructions for performing the CCA procedure during at least one SIFS of the SFIS burst pattern.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, performing the CCA procedure on the second wireless link may include operations, features, means, or instructions for performing the CCA procedure according to the modified CCA parameter.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, modifying the CCA parameter may include operations, features, means, or instructions for increasing a first energy detection threshold for the second wireless link during the first time period to an increased energy detection threshold during the second time period, the modified CCA parameter including the increased energy detection threshold.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining to transmit on the second wireless link during a third time period based on a clear result of the CCA procedure performed during the second time period, and transmitting, during the third time period according, at least a second portion of the message on the first wireless link and a third portion of the message on the second wireless link.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first wireless link includes the first wireless channel in a first radio frequency (RF) spectrum band, and the second wireless link includes a second wireless channel in the first RF spectrum band or a second RF spectrum band.

A method of wireless communication at a first wireless device is described. The method may include establishing a set of wireless links between the first wireless device and a second wireless device, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, configuring a first data unit including a first portion of a message to be transmitted on the first wireless link and a second data unit including a second portion of the message to be transmitted on the second wireless link, the first data unit and the second data unit scheduled to terminate at a same time, transmitting, to the second wireless device based on the configuring, the first data unit on the first wireless link and the second data unit on the second wireless link, and transmitting, to the second wireless device, a signal to solicit an acknowledgement or negative acknowledgement for the first data unit, or the second data unit, or a combination thereof.

An apparatus for wireless communication at a first wireless device is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to establish a set of wireless links between the first wireless device and a second wireless device, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, configure a first data unit including a first portion of a message to be transmitted on the first wireless link and a second data unit including a second portion of the message to be transmitted on the second wireless link, the first data unit and the second data unit scheduled to terminate at a same time, transmit, to the second wireless device based on the configuring, the first data unit on the first wireless link and the second data unit on the second wireless link, and transmit, to the second wireless device, a signal to solicit an acknowledgement or negative acknowledgement for the first data unit, or the second data unit, or a combination thereof.

Another apparatus for wireless communication at a first wireless device is described. The apparatus may include means for establishing a set of wireless links between the first wireless device and a second wireless device, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, configuring a first data unit including a first portion of a message to be transmitted on the first wireless link and a second data unit including a second portion of the message to be transmitted on the second wireless link, the first data unit and the second data unit scheduled to terminate at a same time, transmitting, to the second wireless device based on the configuring, the first data unit on the first wireless link and the second data unit on the second wireless link, and transmitting, to the second wireless device, a signal to solicit an acknowledgement or negative acknowledgement for the first data unit, or the second data unit, or a combination thereof.

A non-transitory computer-readable medium storing code for wireless communication at a first wireless device is described. The code may include instructions executable by a processor to establish a set of wireless links between the first wireless device and a second wireless device, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, configure a first data unit including a first portion of a message to be transmitted on the first wireless link and a second data unit including a second portion of the message to be transmitted on the second wireless link, the first data unit and the second data unit scheduled to terminate at a same time, transmit, to the second wireless device based on the configuring, the first data unit on the first wireless link and the second data unit on the second wireless link, and transmit, to the second wireless device, a signal to solicit an acknowledgement or negative acknowledgement for the first data unit, or the second data unit, or a combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the signal to solicit the acknowledgement may include operations, features, means, or instructions for transmitting a block acknowledgment request to solicit the acknowledgement for at least the first data unit and the second data unit.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a block acknowledgment in response to the transmitted block acknowledgment request.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, on the first wireless link in response to the transmitted signal, the acknowledgment or negative acknowledgement of the first data unit and the second data unit.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the first data unit on the first wireless link and the second data unit on the second wireless link further may include operations, features, means, or instructions for transmitting at least a portion of the first data unit on the first wireless link during a first time period based on a result of a CCA procedure indicating that the first wireless link may be clear, and refraining from transmitting on the second wireless link during the first time period based on a result of the CCA procedure indicating that the second wireless link may be busy.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first wireless link includes the first wireless channel in a first RF spectrum band, and the second wireless link includes a second wireless channel in the first RF spectrum band or a second RF spectrum band.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first wireless link has a first primary channel and the second wireless link has a second primary channel.

A method of wireless communication at a first station is described. The method may include establishing a set of wireless links between the first station and a second station, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, receiving, from the second station, a configuration indicating that the first station may transmit a channel reservation signal to the second station prior to transmitting on the set of wireless links, transmitting, according to the received configuration, a channel reservation signal to the second station based on a result of a CCA procedure on the set of wireless links indicating a clear channel for the first wireless link, receiving a response to the channel reservation signal from the second station, and transmitting on the first wireless link and the second wireless link based on receiving the response to the channel reservation signal.

An apparatus for wireless communication at a first station is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to establish a set of wireless links between the first station and a second station, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, receive, from the second station, a configuration indicating that the first station may transmit a channel reservation signal to the second station prior to transmitting on the set of wireless links, transmit, according to the received configuration, a channel reservation signal to the second station based on a result of a CCA procedure on the set of wireless links indicating a clear channel for the first wireless link, receive a response to the channel reservation signal from the second station, and transmit on the first wireless link and the second wireless link based on receiving the response to the channel reservation signal.

Another apparatus for wireless communication at a first station is described. The apparatus may include means for establishing a set of wireless links between the first station and an second station, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, receiving, from the second station, a configuration indicating that the first station may transmit a channel reservation signal to the second station prior to transmitting on the set of wireless links, transmitting, according to the received configuration, a channel reservation signal to the second station based on a result of a CCA procedure on the set of wireless links indicating a clear channel for the first wireless link, receiving a response to the channel reservation signal from the second station, and transmitting on the first wireless link and the second wireless link based on receiving the response to the channel reservation signal.

A non-transitory computer-readable medium storing code for wireless communication at a first station is described. The code may include instructions executable by a processor to establish a set of wireless links between the first station and a second station, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, receive, from the second station, a configuration indicating that the first station may transmit a channel reservation signal to the second station prior to transmitting on the set of wireless links, transmit, according to the received configuration, a channel reservation signal to the second station based on a result of a CCA procedure on the set of wireless links indicating a clear channel for the first wireless link, receive a response to the channel reservation signal from the second station, and transmit on the first wireless link and the second wireless link based on receiving the response to the channel reservation signal.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the response to the channel reservation may include operations, features, means, or instructions for receiving the response on a soliciting wireless link, the second wireless link, or both.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the configuration may include operations, features, means, or instructions for receiving the configuration via a high efficiency operations element, an EHT operations element, an MLA operations element, or a combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the transmitted channel reservation request indicates a duration of a transmission opportunity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the received response to the channel reservation signal indicates a time duration for one or more additional stations to freeze a countdown.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first station is an access point serving the second station.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second station is an access point serving the first station.

A method of wireless communication at a second station is described. The method may include establishing a set of wireless links between the second station and a first station, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, transmitting, to the first station, a configuration indicating that the first station may transmit a channel reservation signal to the second station prior to transmitting on the set of wireless links, receiving, according to the received configuration, a channel reservation signal from the first station, transmitting, to the first station, a response to the channel reservation signal, and receiving communications from the first station on the first wireless link and the second wireless link based on the transmitted response to the channel reservation signal.

An apparatus for wireless communication at a second station is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to establish a set of wireless links between the second station and a first station, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, transmit, to the first station, a configuration indicating that the first station may transmit a channel reservation signal to the second station prior to transmitting on the set of wireless links, receive, according to the received configuration, a channel reservation signal from the first station, transmit, to the first station, a response to the channel reservation signal, and receive communications from the first station on the first wireless link and the second wireless link based on the transmitted response to the channel reservation signal.

Another apparatus for wireless communication at a second station is described. The apparatus may include means for establishing a set of wireless links between the second station and a first station, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, transmitting, to the first station, a configuration indicating that the station may transmit a channel reservation signal to the second station prior to transmitting on the set of wireless links, receiving, according to the received configuration, a channel reservation signal from the first station, transmitting, to the first station, a response to the channel reservation signal, and receiving communications from the first station on the first wireless link and the second wireless link based on the transmitted response to the channel reservation signal.

A non-transitory computer-readable medium storing code for wireless communication at a second station is described. The code may include instructions executable by a processor to establish a set of wireless links between the second station and a first station, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, transmit, to the first station, a configuration indicating that the station may transmit a channel reservation signal to the second station prior to transmitting on the set of wireless links, receive, according to the received configuration, a channel reservation signal from the first station, transmit, to the first station, a response to the channel reservation signal, and receive communications from the first station on the first wireless link and the second wireless link based on the transmitted response to the channel reservation signal.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining whether to transmit the response to the channel reservation signal based on identifying: downlink transmissions scheduled to be transmitted on the second wireless link; or uplink transmissions being received by the second station from a second station on the second wireless link; or the second station having transmitted a response to a channel reservation request from a second third station on the first wireless link or the second wireless link; or uplink transmissions being received by the AP second station from a second third station on the first wireless link, the second third station hidden from the first station; or a combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the configuration may include operations, features, means, or instructions for transmitting the configuration via a high efficiency operations element, an EHT operations element, an MLA operations element, or a combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the received channel reservation request indicates a duration of a transmission opportunity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the transmitted response to the channel reservation signal indicates a time duration for one or more additional stations to freeze a countdown.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first station is an access point serving the second station; or the second station is an access point serving the first station.

A method of wireless communication at a first wireless device is described. The method may include establishing a set of wireless links between the first wireless device and a second wireless device, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, the first wireless link associated with a first MAC entity of the first wireless device, and the second wireless link associated with a second MAC entity of the first wireless device, identifying one or more data units to be transmitted on the set of wireless links, performing, by the first MAC entity, a CCA procedure on the first wireless link, performing, by the second MAC entity, the CCA procedure on the second wireless link, generating at least one physical layer convergence protocol (PLCP) protocol data unit (PPDU) from the identified one or more data units based on a result of the performed CCA procedure on the first wireless link and the performed CCA procedure on the second wireless link, and transmitting the generated at least one PPDU on the first wireless link, or the second wireless link, or a combination thereof.

An apparatus for wireless communication at a first wireless device is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to establish a set of wireless links between the first wireless device and a second wireless device, the set of wireless links supporting parallel transmissions during a multi-link session and including at least a first wireless link and a second wireless link, the first wireless link associated with a first MAC entity of the first wireless device, and the second wireless link associated with a second MAC entity of the first wireless device, identify one or more data units to be transmitted on the set of wireless links, perform, by the first MAC entity, a CCA procedure on the first wireless link, perform, by the second MAC entity, the CCA procedure on the second wireless link, generate at least one physical layer convergence protocol (PLCP) protocol data unit (PPDU) from the identified one or more data units based on a result of the performed CCA procedure on the first wireless link and the performed CCA procedure on the second wireless link, and transmit the generated at least one PPDU on the first wireless link, or the second wireless link, or a combination thereof.